If you want to build your own you can use 0.0625" (1/16") wall polycarbonate tubing and vinyl caps. Polycarbonate tubing 2" OD x 1-7/8" ID x 1/16" wall is P/N 8585K64, $4.96/linear foot from http://www.mcmaster.com
; 2" ID vinyl caps are P/N 9753K93, $8.94 per 25. Other diameter tube and caps are also available. The caps drive the cost up considerably if you only want one tube but if you get three or four friends together the cost drops to ~$12-17/rod tube depending on tube length (2-3').